In rotary material crushers, a rotor having hammers attached to a peripheral portion of the rotor are driven to rotate at speeds from 300 to 800 rpm, which translates to linear speeds for the hammers from 5000 to 8000 feet per minute, so as to have the hammers impact material such as limestone, and the like, in order to reduce the size of the material. Such crushing of material generates high impact forces on the hammers, which are in turn transferred to the rotor. In view of the high impact forces, it is important to provide a robust means for attaching the hammers to the rotor, but at the same time providing an attaching means which enables the hammers to be easily removed and replaced when excessive wear to the hammers causes them to be unusable.
Conventional means for attaching the hammers to the rotor, such as bolts, or the like, have been found to be undesirable, as the above-described impact forces, besides acting on solely the hammers, also act on the attaching means in a manner that makes removal by conventional means difficult and time consuming.